Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Balance as of January 1	$ 146,421	$ 2,929
Goodwill acquired during the period		143,492
Adjustment to preliminary value of goodwill (Note C)	(242)
Balance at end of period	$ 146,179	$ 146,421